Ok, so you go into your install drive, eg:
X:\\Program Files (x86)\\Steam\\steamapps\\common\\Jagged Alliance 3\\ModTools\\Samples\\Mods
Copy the 3 folders from there to:
X:\\Users\\<YOUR PC LOG IN or NAME>\\AppData\\Roaming\\Jagged Alliance 3
You may have to create a folder called MODS (I did) so then you have
X:\\Users\\<YOUR PC LOG IN or NAME>\\AppData\\Roaming\\Jagged Alliance 3\\Mods
Just copy them to that folder and then in game go to Mods menu and activate